/*
 *  Author: zhaijl 
 *  Url: http://218.1.73.212/down.php
 *  Country: China
 *  
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software based apache mina 2.0 and spring 3.0
 *
 */
package org.cloudy.common.thread ;

public class DefaultSync implements Sync {
	protected boolean inuse = false ;
	public void acquire () throws InterruptedException {
		if ( Thread.interrupted () ) throw new InterruptedException () ;
		synchronized( this ) { 
			try {
				while ( inuse ) wait () ;
				inuse = true ;
			}
			catch ( InterruptedException ex ) {
				notifyAll () ;
				throw ex ;
			}
		}
	}
	
	public synchronized void release () {
		inuse = false ; 
		notifyAll () ;
	}
	
	public synchronized boolean isUsed () {
		return inuse ;
	}
	
	public boolean attempt ( long msecs ) throws InterruptedException {
		if ( Thread.interrupted () ) throw new InterruptedException () ;
		synchronized ( this ) {
			if ( !inuse ) {
				inuse = true ;
				return true ;
			} else if ( msecs <= 0 ) {
				return false ;
			} else {
				long waitTime = msecs ; 
				long start = System.currentTimeMillis () ;
				try {
					for ( ;; ) {
						wait ( waitTime ) ; 
						if (!inuse) {
							inuse = true ;
							return true ;
						} else {
							waitTime = msecs - ( System.currentTimeMillis () - start ) ;
							if ( waitTime <= 0 ) 
							return false ;
						}
					}
				} catch ( InterruptedException ex ) {
					notifyAll () ;
					throw ex ; 
				}
			}
		}
	}

}